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ARTERIES. 



SURGICAL ANATOMY OF THE AXILLA. 



The Axilla is a pyramidal space, situated between the upper and lateral part 

 of the chest, and the inner side of the arm. 



Boundaries. Its apex, which is directed upwards towards the root of the 

 neck, corresponds to the interval between the two Scaleni on the first rib. 

 The base, directed downwards, is formed by the integument, and a thick layer 

 of fascia, extending between the lower border of the Pectoralis Major in front, 

 and the lower border of the Latissimus Dorsi behind ; it is broad internally, at 

 the chest, but narrow and pointed externally, at the arm. The anterior boundary 

 is formed by the Pectoralis Major and Pectoralis Minor muscles, the former 

 covering the whole of the anterior wall of the axilla, the latter covering only 

 its central part. The posterior boundary, which extends somewhat lower than 

 the anterior, is formed by the Subscapularis above, the Teres Major and Latis- 

 simus Dorsi below. On the inner side are the first four ribs with their corres- 

 ponding Intercostal muscles, and part of the Serratus Magnus. On the outer 

 side, where the anterior and posterior boundaries converge, the space is narrow, 

 and bounded by the humerus, the Coraco-brachialis and Biceps muscles. 



Fig. 284. The Axillary Artery, and its Branches. 



Contents. This space contains the axillary vessels, and brachial plexus of 

 nerves, with their branches, some branches of the intercostal nerves, and a large 

 number of lymphatic glands, all connected together by a quantity of fat and 

 loose areolar tissue. 



Their Position. The axillary artery and vein, with the brachial plexus of 

 nerves, extend obliquely along the outer boundary of the axillary space, from 

 its apex to its base, and are placed much nearer the anterior than the posterior 

 wall, the vein lying to the inner or thoracic side of the artery, and altogether 

 concealing it. At the fore part of the axillary space, in contact with the Pec- 



